diff --git a/fractal_client/parser.py b/fractal_client/parser.py
index 52a8fdc2..712c0646 100644
--- a/fractal_client/parser.py
+++ b/fractal_client/parser.py
@@ -927,7 +927,6 @@
 user_set_groups_parser.add_argument(
     "group_ids",
     help="List of the IDs of groups we want the user to be member.",
-    required=True,
     type=int,
     nargs="+",
 )